초록
The purpose of the present study is to investigate the statistical characteristics of m and C in the fatigue crack propagation law, da/dN=C(.DELTA.K)/sup m/ and to studies on the randomness of fatigue crack propagation and retardation behavior. Fatigue tests were perfomed on 32 CT specimens of SPV50 steel under the same one condition. First, the value of m and C were determined for each specimen, and all the data were analyzed statistically. second, the material's resistance to fatigue crack propagation is modeled as a stchastic process, which varies randomly along the crack path. The statistical analysis of the material resistance is performed with the data obtained by constant load controlled tests. Finally, retardation behavior was examined experimentally by using a CT specimen, and a retardation parameters were analyzed statistically.